Coke oven door with wraparound gas channel and membrane

ABSTRACT

The invention relates to a coke oven door ( 1 ) with a gas channel that substantially encloses the oven door and a membrane that is fastened on the coke oven door ( 1 ) and that can be forced against the chamber frame against the action of a spring. The gas channel ( 5 ) is fastened on an at least bilayered membrane ( 3 ).

The invention relates to a coke-oven door with a peripheral gas channeland membrane.

Such a door is known from WO 01/309390. The gas channel on the coke-ovendoor forms a seal system for preventing the entry and exit of vaporsfrom the coke-oven chamber, so that combustion gases cannot leak fromthe coke-over chamber and air cannot get into the coke-oven chamber.

It is important that the door seal or door edge form a tight seal aroundthe entire periphery of the gas channel.

It is known that the change in temperature vertically along the doorcauses the door to bend. There are many suggestions of how to make theseal of the coke-oven door compensate for such deformation. Thesesolutions all have the disadvantage that the spring-loaded seal travelis insufficient to compensate for all deformations.

German 4,103,504 describes a coke-oven door where a membrane is pressedby springs against a frame of the coking chamber. The problem with thissystem is that the membrane must be thick enough that it can withstandthe spring forces, that is the membrane must be sufficientlymechanically rigid. The membrane should not be damaged or destroyed bystandard cleaning procedures. On the other hand, the membrane must berelatively bendable. These two conflicting requirements are never bothmet, so that the deformability of the membrane by the springs isinsufficient and sealing is unsatisfactory.

It is an object of the invention to provide a coke-oven door with aperipheral gas channel whose seal can be moved sufficiently by itssprings that the gas channel can conform to any deformations and alwaysprovide a good seal. In addition the seal system should be compactenough that it is retrofittable on existing coke-oven doors.

This object is achieved by the features of claim 1 or 2.

Further features are seen in the dependent claims.

The invention is based on two general ideas. On the one hand the gaschannel should be spring-biased with a force that is as uniform aspossible over its length while still having the greatest possible rangeof movement or travel; on the other hand the spring force should be soeffective on the gas channel that the biasing force applied to the outerdoor edge is greater or at least equal to the pressure applied at theinner door edge. The seal between the gas channel and the coke-oven dooris ensured by a membrane that must be able to deflect considerably whilestill being quite strong in order to compensate for all possibledeformations. The gas channel has therefore to be flexible so that atevery point the outer door-seal edge bears with the same pressure.

As a result of the flexibility of the membrane it is possible to makethe structure very compact while still allowing it to deflectconsiderably. These factors make it possible using existing mountinghardware to retrofit coke-oven doors where limited space is available.

The embodiment of the membrane in combination with the spring and theresulting large spring travel is in and of itself an invention, that isthis embodiment can be used in standard systems regardless of the typeof gas channel.

If for example conditions preclude the provision of the gas channel, theseal system of the invention can be used to replace any preexisting sealsystem. The membrane with its considerable flexibility ensures bettersealing even with conventional seal systems.

The seal system according to the invention makes it possible tocompensate for any possible deformations of the chamber frame and alsoof the coke-oven door so that at any time a complete seal is guaranteed.When using the gas channel the seal system also has the advantagesdescribed in WO 01/30939, that is gas-pressure equalization between thegas channel and the coke-oven chamber and so that as a result thecrude-gas pressure on the outer seal edge is more easily controlled.

According to the invention the membrane is formed of at least twosheets. This embodiment has the advantage that the elastic deformabilityof the membrane is improved with respect to a membrane having a singlesheet of uniform thickness. As a result of the elastic properties of themembrane, the membrane returns to the starting position under springforce when the pressure on it is lessened.

The membrane according to the invention can be sandwiched together ofseveral different materials. The membrane sheet closest to the gaschannel is made corrosion resistant while the central membrane (e.g.spring steel) serves as spring and the upper one contributes to thespring function.

According to a further embodiment of the invention, the membrane isformed of two sheets. The individual sheets are more elastic than asingle sheet of a thickness equal to the combined thickness of bothsheets, and the sheets can slide on each other on deformation.

The membrane can also be made as a laminate. In the simplest case thetwo sheets are joined together. This can be done for example by webs orother materials, e.g. plastics or glues. They can also be joined by thetar recovered in the coke plant.

The individual sheets of the membrane can have different thicknesses. Inthis manner the bending characteristics of the membrane can be variedover a wide range and optimally matched to requirements.

The individual sheets of the membrane are no more than one centimeterthick. With this embodiment the membrane can be made of quite a fewindividual sheets that can shift relative to one another. In this mannerouter faces of the individual sheets slide on one another. The membraneis thus more flexible and can deform elastically more. As a result morespring travel is possible. This embodiment has the advantage that damageto one of the individual sheets is automatically sealed by the stickycondensate (tar).

It is also possible that the sheets that seal the door opening areheat-and corrosion resistant and the other sheets are constituted sothat they impart sufficient bendability to the membrane.

According to a further embodiment of the invention at least one of thesheets is a spring. As a result, the membrane itself contributes to thespring action.

The sheets forming the membrane can be molded. Thus any possible type ofspring or membrane sheet known in the art can be used.

It is of course also possible to combine individual sheets with theabove-described characteristics.

The membrane according to the invention can be made of any type ofsprings known in the art. As a result of its considerable bendability itcan accommodate any spring travel.

It is also possible to make the membrane as the spring. To this end oneor more of the sheets of the membrane is made as a spring.

According to an embodiment the spring is formed as a stack of leafsprings that are jointly fixed to the door plate above the membrane andthat press on the gas channel. To this end in order for the seal edgesto compensate better for deformations, the leaf springs are formed assegments.

Another possibility is to provide the door plate with mounting elementsfor carrying a push rod that presses on the gas passage. The push rodcan be biased for example with spring washers, coil springs, or even bya hydraulic or pneumatic unit against the gas channel.

A further possibility of biasing the gas channel is to mount a leafspring on the door plate. In this embodiment the leaf spring can itselfbe a relatively stiff element with limited elasticity and the actualspring travel is created by the spring mount.

The spring mount can be done e.g by spring washers that bear on a screw.A further embodiment is mounting a spring on a spring bar. It is alsopossible to make a spring such that it assumes the spring function ofthe spring washers or spring bar. This embodiment has the advantage thata single spring part can be used to take care of two different springfunctions.

Such an arrangement ensures that the gas channel is mounted in a springsystem with a relatively large travel. The spring travel is created bythe stroke of the spring and the stroke that is imparted to the springby its mount.

The membrane must be made such that it can follow the full springtravel. On the other hand the membrane must be sufficiently springy thatit returns to its starting position. This of course applies to all thespring components of the spring system.

According to the invention it is possible to provide a rigid double seal(gas channel) with a large spring travel on the door frame, the biasingforce being the same over its entire length.

With the above-described spring system it is possible to create anydesired biasing force with the desired distribution and springcharacteristic, that is the inner and outer edges of the gas channel canbe biased with different or the same biasing forces. Thus for examplevarious leaf springs can be used together so as to produce a springeffect that increases with increasing deflection. This can be doneeither by changing the shape or length of the leaf springs or byproviding stops spaced at appropriate distances from the spring.

The same possibilities also exist with other spring systems. When usingthe system with pusher rods, attention must be paid that the biasingforce is spread out by an appropriate pressure-distributing bar. Such apressure-distributing bar must be so flexible that the gas channel canfit to the nonplanarities of the chamber frame.

The springs can also be prestressed to different extents to achieve thedesired biasing.

The springs can also be made as a laminate. To this end all the knownsystems can be used. Since the style of lamination of the membranes insprings affects flexibility, lamination can be used both for the springsas well as for the membrane.

Such layering can be such that passages are created between theindividual layers of the spring or of the membrane. The passages can beset up to conduct an appropriate heating or cooling medium. It is alsopossible to fill the passages with insulation.

The gas chamber must be set up such that it can compensate forirregularities and deformations of the chamber frame. On the other handthe gas chamber must have a large enough cross section that crude gascan be carried away without any pressure buildup. In any case the gaschannel has an inner and outer seal edge. The gas channel must be asflexible as possible at these edges. It is therefore possible forexample to make the edges of the walls of the gas channel at the sealingedges somewhat thinner or to cut them away or bend them back and thusincrease the bendability in this region.

It is also possible to mount a door-sealing lip on the inner or outerwall of the gas channel. The gas channel can also be formed ofappropriately formed elements of the membrane or of the spring (leafsprings).

A particular problem is sealing coke-oven doors at the corners. Theinvention suggests that the membranes at the corners are made of onepiece, that is the individual layers of the membrane are made of onepiece for the upper and lower regions such that they form a U. Themembrane that seals the long sides of the coke-oven door is fitted tothis U-shape. With this system a long-lived gas seal is created sincethe seams lie outside the strongly loaded corner regions.

The individual parts of the membrane can be connected together bywelding. As a result of the construction of the membrane as individuallayers, the membrane can be connected together such that the seams ofthe individual layers are offset to one another. As a result of thisoverlapping of the individual layers of the membrane in this regionthere is excellent gas sealing. Since in these connection regions themembranes have the same thickness, the individual membrane sheets mustbe butted. This butting can be done in different ways. In the simplestcase the individual membrane layers are cut square and pushed togetheredgewise. It is also possible to butt the membrane layers on diagonals.The edges of the individual membrane sheets can also be beveled so thatthey meet at a sharp edge. The diagonal orientation of the butting edgesincreases the length of the seal surfaces while the angling (sharpening)of the membrane layers increases the seal surface.

With the membrane according to the invention with its layeredconstruction it is possible to mount the membrane in corner regions. Inthis embodiment the individual membrane layers are of reduced thicknesswhere they overlap so that the two overlapping layers together have thethickness of a single layer. This can be done for example by beveling(sharpening) or by appropriately milling away (forming a step).

These connections are stabilized by the tar present in the crude gasthat gets into the cracks or interstices. As a further embodiment, tarcan also be used as a glue or adhesive in the construction of themembrane to unite the individual membrane layers.

In the embodiment of a membrane having layers less than one millimeterthick, the individual membrane layers can be overlapped without specialprocedures in the joint regions. It is sufficient to offset the membranesheets in the joint regions.

Since the profile of the gas channel engages the chamber frame and isnot shaped by the spring, in these region there are no stresses or onlyminor ones. The gas channel can have mitered corners. Since in thisregion the weld seams are only subject to modest forces another type ofjoint can be used. It is also possible to insert one part of the gaschannel into another at the corner. Such an inserted joint is shown inthe drawing. The exact type of insert connection can be provided at anydesired region of the gas channel.

The seal system according to the invention with membrane, gas channel,and spring is exceptionally good for sealing leaky coke-oven doors. Itis possible to retrofit all coke-oven doors on the market. The membranewith spring according to the invention can also be used to retrofit allthe known seal systems.

The parts described above, claimed, and described specifically canaccording to the invention be made in different sizes and shapes, ofdifferent materials, and according to different principles so that thescope of the invention is not limited.

Further specifics, features, and advantages of the invention are seenfrom the following description and the corresponding drawing in which byway of example several embodiments of the invention are shown.

Therein:

FIG. 1 is a partial section through a coke-oven door with gas channel,membrane, and leaf spring;

FIG. 2 is an embodiment with a pusher rod and spring washers;

FIG. 3 is an embodiment with a spring-mounted biasing unit;

FIGS. 4 a and 4 b are an embodiment with a biasing unit formed by astructural element;

FIG. 5 is an embodiment of a multilayer membrane;

FIG. 6 is an embodiment wherein the biasing unit, membrane, and gaspassage are all one assembly;

FIG. 7 is an embodiment of the gas channel with a flexible door-sealingedge;

FIG. 8 is the embodiment of FIG. 1 wherein the biasing force is appliedin the region of the outer door-seal edge;

FIG. 9 is an embodiment of the corner of the gas channel with plug-ininterfit;

FIG. 10 is an embodiment with a considerable range of biased movement.

FIG. 1 is a partial view of a coke-oven door 1 at its peripheral gaschannel 5. A membrane 3 is fixed by a mounting element 4 on a door plate2 of the coke-oven door 1. The mounting element 4 has an edge bevel 4 a.The membrane 3 is comprised of three vertically spaced sheets 3′, 3″,and 3′″. The gas channel 5 is defined between an outer door edge 5 a andan inner door edge 5 b at an outer periphery of the membrane 3. The gaschannel 5 has on the inner door-seal edge 5 b an edge bevel 5 c. Leafsprings 6 that are supported on a mounting element 7 are carried on themounting element 4. The mounting element 7 also has an edge bevel 7 a.The leaf springs 6 press against a bar 8 that is secured to the edge ofthe membrane 3 at the gas channel 5. The gas channel is pressed by theleaf springs 6 against the chamber frame 9 of an unillustrated coke-ovenchamber. Thus the gas channel 5 seals against the chamber frame 9.Movements caused by deformations of the chamber frame 9 and/or of thecoke-oven door 1 are compensated for by the leaf springs 6 in that thegas channel 5 is always pressed sealingly against the chamber frame 9.The flexible membrane 3 offers very little resistance to the leafsprings 6. The bevels 4 a and 5 c of the mounting element 4 and gaschannel 5 allow the membrane 3 to follow the movements created by theleaf springs 6. The range of movement of the coke-oven door 1 is shownby arrows A and B. The bevel 7 a of the mounting element 7 creates along lever arm and thus a larger range of movement of the leaf springs6.

FIG. 2 shows another embodiment of the seal system according to theinvention. A holder 11 for a pusher rod 10 is mounted on the door plate2 with the membrane 3 and the mounting element 4. The pusher rod 10carries stacks of spring washers 12 that urge the pusher rod 10 towardthe bar 8 and toward the gas channel 6 as a pressure-distributing beamand thereby press the gas channel 5 against the chamber frame 9. Thespring washers 12 are prestressed by lock nuts 13.

FIG. 3 shows how the gas channel 5 is pressed by a leaf spring 15against the chamber frame 9. The leaf spring 15 is supported by stacksof spring washers 17 on a screw 16 that is in turn mounted on themounting element 4. With this spring mount there is a considerable rangeof movement for the leaf spring 15.

FIG. 4 a shows a further embodiment of the seal system for a coke-ovendoor 1 having a spring that is formed as a biasing element 20. Thespring biasing element 20 pushes via the bar 8 and the membrane 3 on thegas channel 5 that is thus pressed against the chamber frame 9. Thedepth of engagement of the spring-biasing part 20 in a holder element 21as shown by double-headed arrow A allows the spring travel andcharacteristics to be varied.

FIG. 4 b shows the same embodiment of the spring. A screw 22 allows thespring part 20 to be prestressed.

FIG. 5 shows a membrane 25 formed of multiple layers. The membrane 25 iscomprised of membrane sheets 26, 27, 28, and 29. The membrane sheets 27and 28 are connected together by webs 30. The webs 30 form passages 31between the membrane sheets 27 and 28. The passages 31 can hold a fluidso that the passages 31 serve as cooling or heating passages. It is alsopossible that the passages 31 and/or the spaces between the membranesheets 26 and 27 or 28 and 29 are filled with insulation so that themembrane 25 or at least part of the membrane 25 functions as aninsulating layer.

FIG. 6 shows a membrane 40 with membrane sheets 41 and 42. The membranesheets 41 and 42 are bent at right angles at their free ends and areclamped together at their other ends so that the gas channel 5 is formedbetween two of the right-angle end portions. At lower outer ends of theright-angle end portions the membrane sheets 41 and 42 have bent-backedges 43′. These bent edges 43 form seal edges 43′ that seal the gaschannel 5 relative to the chamber frame 9. Leaf springs 44, 45, and 46press against the membrane 40. The leaf springs 44, 45, and 46 are ofdifferent lengths. In this manner the spring force increases withincreasing deflection.

FIG. 7 shows the gas channel 5 with an outer door-seal edge 50 and aninner door-seal edge 51. The inner door-seal edge 51 has at its lowerend a groove 52. Below the groove 52 the inner door-seal edge 51 isformed with a bevel 54 so that it forms a door-sealing lip 56. The outerdoor-sealing edge 50 similarly has on its lower edge a groove 53 and abevel 55. The bevel 55 extends over the entire width of the door-sealedge 50. In this manner it is possible to press with a spring force Fdirectly against the door-seal lip 57 and thus get flexibleaccommodation to the chamber frame 9.

FIG. 8 shows how the membrane 3 and the leaf spring 6 are secured withthe mounting element 4 to the door plate 2. The lowermost leaf spring ofthe leaf spring assembly 6 is bent over on its free end and thus formspoint or line contact between the membrane 3 and the outer door-sealedge of the gas channel 5. The point or line contact of the leaf spring6 can be increased by pushing a wedge 60 between the individual leafsprings of the leaf-spring assembly 6.

FIG. 9 shows a corner region of the gas channel 5. The gas channel 5 isformed by connection in the direction of arrow A at a corner region. Tothis end the right-hand part of the gas channel 5 is inserted into anopening 64 in the left-hand part. An opening 65 in the right-hand partof the gas channel permits unhindered gas flow at the corner region ofthe gas channel 5. The fit is tight enough that further connectingelements for the two parts of the gas channel 5 are not needed since anyleaks are plugged by tar. It is also possible to use tar or anotheradhesive to connect the two gas-channel parts.

FIG. 10 shows show a leaf spring 70 bears with a slide face 71 on thebar 8 and thus against the membrane 3 and the gas channel 5. When thecoke-oven door 1 and/or the chamber frame 9 deform as shown by arrows Aand B the leaf spring 70 shifts with its slide face 7 a along an edge ofthe bar 8. The extent of spring travel is determined by the stroke ofthe leaf spring 70, the stroke defined by angular deformation of theslide face 7 a and the leaf spring 70, and the sliding of the bar 8along the slide face. The sum of these three factors produces aconsiderable amount of possible movement. The inner door-seal edge 5 bof the gas channel forms a gap 72. On movement of the coke-oven door 1in the direction of the arrow B the outer door-seal edge 5 a of the gaschannel engages the chamber frame 9. Further movement in this directionfirst presses the outer door-seal edge 5 a of the gas channel on thechamber frame 9. On further movement the inner edge 5 b of the gaschannel seats and the gap 72 is closed. In this manner the already largespring travel of this system is further increased. On opposite movementof the coke-oven door in the direction of the arrow A the innerdoor-seal edge 5 b of the gas channel first lifts off the chamber frame9 while the outer door-seal edge 5 a of the gas channel 5 still seals. 1 coke-oven door 25 membrane  2 door plate 26 membrane sheet  3membrane 27 membrane sheet  3′ sheet 28 membrane sheet  3″ sheet 29membrane sheet  3″′ sheet 30 web  4 mounting element 31 passages  5 gaschannel 40 membrane  5a door-seal edge 41 membrane sheet  5b door-sealedge 42 membrane sheet  6 leaf springs 43 bent end  7 mounting element43′ seal edge  8 strip 44 leaf spring  9 chamber frame 45 leaf spring 10pusher rod 46 leaf spring 11 mount 50 outer door seal 12 spring washers51 inner door seal 13 nuts 52 groove 15 leaf springs 53 groove 16 screw54 bevel 17 spring washers 55 bevel 20 spring 56 door seal 21 mountingelement 57 door seal 22 spring 60 wedge 64 opening 65 opening 70 leafspr8ing 71 slide face 72 gap A arrow B arrow

1-32. (canceled)
 33. In combination with a coke-oven door having anannular periphery normally juxtaposed with an annular door frame, a sealassembly comprising: an annular membrane formed of at least two flexibleand relatively displaceable sheets each having an annular innerperiphery and an annular outer periphery; a U-section channel fixed tothe outer peripheries of the sheets, open toward the door, and havingannular inner and outer edges; mounting means for securing the innerperiphery to the periphery of the door; and spring means for urging theedges of the channel with a spring force against the door frame. 34.(canceled)
 35. The door seal assembly defined in claim 34 wherein thereat least four sheets.
 36. The door seal assembly defined in claim 33wherein the sheets are of different thicknesses.
 37. The door sealassembly defined in claim 33 wherein at least one of the sheets iselastically deformable and forms part of the spring means.
 38. The doorseal assembly defined in claim 33 wherein the sheets are of differentmaterials.
 39. The door seal assembly defined in claim 33 wherein thespring means includes a plurality of leaf springs each having an innerend attached to the door and an outer end bearing on the membrane andchannel.
 40. The door seal assembly defined in claim 39 wherein the leafsprings are of different lengths.
 41. The door seal assembly defined inclaim 39 wherein the leaf springs are spaced apart.
 42. The door sealassembly defined in claim 39 wherein the outer ends of the leaf springsare bent toward the door.
 43. The door seal assembly defined in claim 39wherein the spring means further includes a wedge engageable between theleaf springs.
 44. The door seal assembly defined in claim 33 wherein thespring means includes an array of push rods bearing against the membraneand channel, and respective springs engaged between the push rods andthe door.
 45. The door seal assembly defined in claim 44 wherein thesprings are each constitute by a stack of spring washers.
 46. The doorseal assembly defined in claim 44 wherein the spring means furtherincludes a pressure-equalization bar extending generally parallel to thedoor between the array or rods on one side and the channel and membraneon the other side.
 47. The door seal assembly defined in claim 44wherein the spring means includes abutment screws fixed on the membraneand engageable with the door.
 48. The door seal assembly defined inclaim 33, further comprising webs extending between the membrane sheetsand forming passages, whereby a heat-exchange liquid can be flowedthrough the passages.
 49. The door seal assembly defined in claim 33wherein the sheets are leaf springs.
 50. The door seal assembly definedin claim 33 wherein the sheets are planar and generally parallel. 51.The door seal assembly defined in claim 50 wherein the sheets flatlyengage one another.
 52. The door seal assembly defined in claim 50wherein the sheets are spaced from one another.
 53. In combination witha coke-oven door having an annular periphery normally juxtaposed with anannular door frame, a seal assembly comprising: an annular membraneformed of at least two flexible and relatively displaceable sheets; andspring means for urging the membrane with a spring force against thedoor frame.